Hi all,

as described before, I am currently implementing draft-ietf-soc-overload-control-02 (http://tools.ietf.org/html/draft-ietf-soc-overload-control-02) and I have to add one or more additional parameters to the (remaining) topmost Via-header in SIP-responses.

So, if my server (server10.biloxi.com) gets (e.g., from rfc3261) a response from a downstream server like SIP/2.0 200 OK Via: SIP/2.0/UDP server10.biloxi.com ;branch=z9hG4bKnashds8;received=192.0.2.3 Via: SIP/2.0/UDP bigbox3.site3.atlanta.com ;branch=z9hG4bK77ef4c2312983.1;received=192.0.2.2 Via: SIP/2.0/UDP pc33.atlanta.com ;branch=z9hG4bK776asdhds ;received=192.0.2.1 To: Bob sip:bob@biloxi.com;tag=a6c85cf ...

if of course have to remove the topmost via and then - according to the oc-draft - add additional oc-paramters (in this example "oc=20"). The resulting SIP response looks like this:

SIP/2.0 200 OK Via: SIP/2.0/UDP bigbox3.site3.atlanta.com ;branch=z9hG4bK77ef4c2312983.1;received=192.0.2.2;oc=20 Via: SIP/2.0/UDP pc33.atlanta.com ;branch=z9hG4bK776asdhds ;received=192.0.2.1 To: Bob sip:bob@biloxi.com;tag=a6c85cf ...

Well, my question is now, where to modify/add this parameter.

If I understood the code correctly, the function "build_res_buf_from_sip_buf()" (in msg_translator.c) might be the right location to add the modification. My aditional oc-parameter is stored in a char* and the msg is stored in the struct sip_msg. I saw that many request-modifications are done with the "lumps"-functions, but I don't get an idea how they are helping to solve my problem.

So, how can I add this char* to the end of the remaining topmost via-header?

Any hint/idea?

br Michael Hirschbichler